scholarly journals Finding pythons in unexpected places

2021 ◽  
Author(s):  
Netta Engelhardt ◽  
Geoff Penington ◽  
Arvin Shahbazi-Moghaddam
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Mixed State ◽  
Crucial Role ◽  
State Dependence ◽  
Extremal Surface ◽  
Black Hole Interior ◽  
Exponential Complexity

Abstract We argue that novel (highly nonclassical) quantum extremal surfaces play a crucial role in reconstructing the black hole interior even for isolated, single-sided, non-evaporating black holes (i.e. with no auxiliary reservoir). Specifically, any code subspace where interior outgoing modes can be excited will have a quantum extremal surface in its maximally mixed state. We argue that as a result, reconstruction of interior outgoing modes is always exponentially complex. Our construction provides evidence in favor of a strong Python’s lunch proposal: that nonminimal quantum extremal surfaces are the exclusive source of exponential complexity in the holographic dictionary. We also comment on the relevance of these quantum extremal surfaces to the geometrization of state dependence in the typicality arguments for firewalls.

scholarly journals Islands and Page curves of Reissner-Nordström black holes

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Xuanhua Wang ◽  
Ran Li ◽  
Jin Wang
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Hawking Radiation ◽  
Entanglement Entropy ◽  
Additional Term ◽  
Current Case ◽  
Information Paradox ◽  
Extremal Surface ◽  
Four Dimensions ◽  
Black Hole Information

Abstract We apply the recently proposed quantum extremal surface construction to calculate the Page curve of the eternal Reissner-Nordström black holes in four dimensions ignoring the backreaction and the greybody factor. Without the island, the entropy of Hawking radiation grows linearly with time, which results in the information paradox for the eternal black holes. By extremizing the generalized entropy that allows the contributions from the island, we find that the island extends to the outside the horizon of the Reissner-Nordström black hole. When taking the effect of the islands into account, it is shown that the entanglement entropy of Hawking radiation at late times for a given region far from the black hole horizon reproduces the Bekenstein-Hawking entropy of the Reissner-Nordström black hole with an additional term representing the effect of the matter fields. The result is consistent with the finiteness of the entanglement entropy for the radiation from an eternal black hole. This facilitates to address the black hole information paradox issue in the current case under the above-mentioned approximations.

scholarly journals Defect extremal surface for reflected entropy

2022 ◽  
Vol 2022 (1) ◽  
Author(s):  
Tianyi Li ◽  
Ma-Ke Yuan ◽  
Yang Zhou
Keyword(s):  
Black Hole ◽  
Mixed State ◽  
Entanglement Entropy ◽  
Quantum Defect ◽  
Entropy Measure ◽  
Extremal Surface ◽  
Decomposition Procedure ◽  
Hole Model ◽  
Quantum Defect Theory

Abstract Defect extremal surface is defined by extremizing the Ryu-Takayanagi formula corrected by the quantum defect theory. This is interesting when the AdS bulk contains a defect brane (or string). We introduce a defect extremal surface formula for reflected entropy, which is a mixed state generalization of entanglement entropy measure. Based on a decomposition procedure of an AdS bulk with a brane, we demonstrate the equivalence between defect extremal surface formula and island formula for reflected entropy in AdS3/BCFT2. We also compute the evolution of reflected entropy in evaporating black hole model and find that defect extremal surface formula agrees with island formula.

scholarly journals Effects of the Hubble parameter on the cosmic growth of the first quasars

2020 ◽  
Vol 496 (1) ◽  
pp. 888-893 ◽  
Author(s):  
Rafael C Nunes ◽  
Fabio Pacucci
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Hubble Parameter ◽  
Crucial Role ◽  
Seed Mass ◽  
Early Growth ◽  
Supermassive Black Holes ◽  
Initial Mass ◽  
Seed Formation ◽  
Mcmc Approach

ABSTRACT Supermassive black holes (SMBHs) play a crucial role in the evolution of galaxies and are currently detected up to $z$ ∼ 7.5. Theories describing black hole (BH) growth are challenged by how rapidly seeds with initial mass $M_\bullet \lesssim 10^5 \, {\rm M_\odot }$, formed at $z$ ∼ 20–30, grew to $M_\bullet \sim 10^9 \, {\rm M_\odot }$ by $z$ ∼ 7. Here we study the effects of the value of the Hubble parameter, H0, on models describing the early growth of BHs. First, we note that the predicted mass of a quasar at $z$ = 6 changes by $\gt 300{{\ \rm per\ cent}}$ if the underlying Hubble parameter used in the model varies from H0 = 65 to H0 = 74 km s−1Mpc−1, a range encompassing current estimates. Employing an MCMC approach based on priors from $z$ ≳ 6.5 quasars and on H0, we study the interconnection between H0 and the parameters describing BH growth: seed mass Mi and Eddington ratio fEdd. Assuming an Eddington ratio of fEdd = 0.7, in agreement with previous estimates, we find $H_0 = 73.6^{+1.2}_{-3.3}$ km s−1Mpc−1. In a second analysis, allowing all the parameters to vary freely, we find log (Mi/M⊙) > 4.5 (at 95 per cent CL), $H_0 = 74^{+1.5}_{-1.4}$ km s−1Mpc−1 and $f_{\rm Edd}=0.77^{+0.035}_{-0.026}$ at 68 per cent CL. Our results on the typical Eddington ratio are in agreement with previous estimates. Current values of the Hubble parameter strongly favour heavy seed formation scenarios, with $M_i \gtrsim 10^4 \, {\rm M_\odot }$. In our model, with the priors on BH masses of quasars used, light seed formation scenarios are rejected at ∼3σ.

scholarly journals BLACK HOLES RADIATE BUT DO NOT EVAPORATE

2005 ◽  
Vol 14 (12) ◽  
pp. 2257-2261 ◽  
Author(s):  
HRVOJE NIKOLIĆ
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Hawking Radiation ◽  
Negative Energy ◽  
Black Hole Mass ◽  
Black Hole Radiation ◽  
Semiclassical Gravity ◽  
Black Hole Interior ◽  
Semiclassical State ◽  
Infinite Temperature

During the black hole radiation, the interior contains all the matter of the initial black hole, together with the negative energy quanta entangled with the exterior Hawking radiation. Neither the initial matter nor the negative energy quanta evaporate from the black hole interior. Therefore, the information is not lost during the radiation. The black hole mass eventually drops to zero in semiclassical gravity, but this semiclassical state has an infinite temperature and still contains all the initial matter together with the negative energy entangled with the exterior radiation.

scholarly journals Truly two-dimensional black holes under dimensional transitions of spacetime

2021 ◽  
Author(s):  
Wanpeng Tan
Keyword(s):  
Phase Transition ◽  
Black Holes ◽  
Black Hole ◽  
Degrees Of Freedom ◽  
Massive Star ◽  
Majorana Fermions ◽  
Two Dimensional ◽  
Gauge Bosons ◽  
The Core ◽  
Black Hole Interior

A sufficiently massive star in the end of its life will inevitably collapse into a black hole as more deconfined degrees of freedom make the core ever softer. One possible way to avoid the singularity in the end is by dimensional phase transition of spacetime. Indeed, the black hole interior, two-dimensional in nature, can be described well as a perfect fluid of free massless Majorana fermions and gauge bosons under a 2-d supersymmetric mirror model with new understanding of emergent gravity from dimensional evolution of spacetime. In particular, the 2-d conformal invariance of the black hole gives rise to desired consistent results for the interior microphysics and structures including its temperature, density, and entropy.

scholarly journals From neutron and quark stars to black holes

2020 ◽  
Author(s):  
Wanpeng Tan
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Quark Matter ◽  
Mean Field ◽  
New Physics ◽  
Quantum Theories ◽  
Spacetime Geometry ◽  
Quark Stars ◽  
Quantum Particles ◽  
Black Hole Interior

New physics and models for the most compact astronomical objects - neutron / quark stars and black holes are proposed. Under the new supersymmetric mirror models, neutron stars at least heavy ones could be born from hot deconfined quark matter in the core with a mass limit less than $2.5 M_\odot$. Even heavier cores will inevitably collapse into black holes as quark matter with more deconfined quark flavors becomes ever softer during the staged restoration of flavor symmetry. With new understanding of gravity as mean field theories emergent from the underlying quantum theories for providing the smooth background spacetime geometry for quantum particles, the black hole interior can be described well as a perfect fluid of free massless Majorana fermions and gauge bosons under the new genuine 2-d model. In particular, the conformal invariance on a 2-d torus for the black hole gives rise to desired consistent results for the interior microphysics and structures including its temperature, density, and entropy. Conjectures for further studies of the black hole and the early universe are also discussed in the new framework.

scholarly journals Symmetries of the black hole interior and singularity regularization

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Marc Geiller ◽  
Etera R. Livine ◽  
Francesco Sartini
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Black Hole Physics ◽  
Proper Time ◽  
White Hole ◽  
Formula Group ◽  
Physical Symmetry ◽  
Black Hole Interior ◽  
Group Quantization

We reveal an \mathfrak{iso}(2,1)𝔦𝔰𝔬(2,1) Poincar'e algebra of conserved charges associated with the dynamics of the interior of black holes. The action of these Noether charges integrates to a symmetry of the gravitational system under the Poincar'e group ISO(2,1)(2,1), which allows to describe the evolution of the geometry inside the black hole in terms of geodesics and horocycles of AdS{}_22. At the Lagrangian level, this symmetry corresponds to M"obius transformations of the proper time together with translations. Remarkably, this is a physical symmetry changing the state of the system, which also naturally forms a subgroup of the much larger \textrm{BMS}_{3}=\textrm{Diff}(S^1)\ltimes\textrm{Vect}(S^1)BMS3=Diff(S1)⋉Vect(S1) group, where S^1S1 is the compactified time axis. It is intriguing to discover this structure for the black hole interior, and this hints at a fundamental role of BMS symmetry for black hole physics. The existence of this symmetry provides a powerful criterion to discriminate between different regularization and quantization schemes. Following loop quantum cosmology, we identify a regularized set of variables and Hamiltonian for the black hole interior, which allows to resolve the singularity in a black-to-white hole transition while preserving the Poincar'e symmetry on phase space. This unravels new aspects of symmetry for black holes, and opens the way towards a rigorous group quantization of the interior.

scholarly journals Remarks on non-singular black holes

2018 ◽  
Vol 168 ◽  
pp. 01001 ◽  
Author(s):  
Valeri P. Frolov
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Apparent Horizon ◽  
External Observer ◽  
Quantum Radiation ◽  
Black Hole Background ◽  
Black Hole Interior ◽  
Mass Inflation ◽  
The Given ◽  
Self Consistency

We briefly discuss non-singular black hole models, with the main focus on the properties of non-singular evaporating black holes. Such black holes possess an apparent horizon, however the event horizon may be absent. In such a case, the information from the black hole interior may reach the external observer after the complete evaporation of the black hole. This model might be used for the resolution of the information loss puzzle. However, as we demonstrate, in a general case the quantum radiation emitted from the black hole interior, calculated in the given black hole background, is very large. This outburst of the radiation is exponentially large for models with the redshift function α = 1. We show that it can be suppressed by including a non-trivial redshift function. However, even this suppression is not enough to guarantee self-consistency of the model. This problem is a manifestation of a general problem, known as the "mass inflation". We briefly comment on possible ways to overcome this problem in the models of non-singular evaporating black holes.

scholarly journals Fractionated branes and black hole interiors

2015 ◽  
Vol 24 (12) ◽  
pp. 1543004 ◽  
Author(s):  
Emil J. Martinec
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
String Theory ◽  
Inner Horizon ◽  
Black Hole Interior ◽  
Tension State ◽  
Low Tension

Combining a variety of results in string theory and general relativity, a picture of the black hole interior is developed wherein spacetime caps off at an inner horizon and the inter-horizon region is occupied by a Hagedorn gas of a very low tension state of fractionated branes. This picture leads to natural resolutions of a variety of puzzles concerning quantum black holes.

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